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The infantry's 40 mm punch: new designs and ammunition types are extending the capabilities of the shoulder-fired 40-mm grenade launcher. With lightweight alloys, composite materials and new warhead technologies these weapons are a far cry from their 1950s ancestors.


The origin of the 40-mm grenade launcher can be traced back to 1951 when the US Army began its search for an individual weapon that could deliver a high-explosive payload in the gap between the maximum range of a hand grenade, possibly 30 metres thrown, and the 400-metre minimum range of its light mortars. Picatinny Arsenal developed a 40 x 46 mm low-velocity cartridge that was classified as the M406 40-mm high-explosive fragmentation grenade, and in 1961 the army fielded the first production examples of the M79 grenade launcher. This was a single-shot, break-open weapon with a rifled barrel and an adjustable ladder-type rear sight graduated in 25-metre increments from 75 to 375 metres. The major drawback with the M79 was that the grenadier had to carry a 'backup' weapon such as a pistol or a rifle. Throughout the Vietnam War US Army and US Marine Corps rifle squads appreciated the firepower provided by a skilled grenadier armed with his 'Blooper'.

With the introduction of the M16 5.56-mm assault rifle in the mid-1960s the army sponsored the development of the M203, an under-barrel grenade launcher (UGL) attachment that fires the same low-velocity ammunition as the M79. Since 1969 the M203 has been fielded by the armed forces of almost 40 countries and the design provided the inspiration for similar weapons developed by numerous countries to fit their own pattern rifles. The M203 attaches to any standard M16 series rifle by removing the weapon's hand-guard and replacing it with the M203, which includes a new hand-guard and a rifled aluminium barrel. The unloaded launcher weighs 1.36 kg. A battle sight, graduated from 50 to 250 metres is mounted on the hand-guard and a quadrant sight, adjustable for 50 to 400 metres, can also be mounted to the rifle's carrying handle. The barrel slides forward in the receiver assembly to allow ammunition to be loaded. The M203 has an effective range of 150 metres against point targets and 350 metres against area targets. The 203A1 was designed for use with the M4 5.56-mm carbine. The Knights Armament M203A2 attaches to all M16/M4 Modular Weapon System (MWS) rifles and carbines. The MWS includes the M203 Grenade Launcher Rail System, built by Wilcox, which provides for range adjustments from 40 to 400 metres and allows targets to be engaged at night.


The primary grenade in US service is the low-velocity M433 high-explosive, dual-purpose anti-armour and anti-personnel round which has both fragmentation effects and is able to penetrate up to 76 mm of armour. Other rounds include the M583 star flare parachute round, the M781 practice dye and M918 target practice round and the M1006 and M1029 non-lethal rounds.

The M1006 delivers a sponge cartridge to disorient or incapacitate individuals at ranges from 10 to 50 metres. Since the start of the US-led global war on terrorism the army has fielded the M1060 thermobaric round. According to the Program Executive Officer Soldier this provides, << Increased probability of kill within lethal radius and improved effectiveness against defilade targets. This ammunition will have the ability to neutralise a larger variety of indoor and outdoor targets. It provides increased capability versus buildings and bunkers >>.

In 2007 an infantry battalion commander in Iraq told the National Defense Industrial Association's 2007 ammunition symposium that the 40-mm round is << accurate and reliable >> and the << blast, shock and fragmentation are excellent >> but noted that the M203 is << awkward in close quarters and ammo is tough to carry with body armor >>.


A New Generation

Although in 2005 the army cancelled the planned acquisition of the Heckler & Koch XM8 5.56 mm carbine family to replace the M16/M4, the associated XM320 40 mm Grenade Launcher Module (GLM) has survived as a replacement for the M203 M16/M4 and as a standalone weapon. The single-shot M320 is safer and more reliable than the M203 and accurately delivers by day and night the current ammunition family to its maximum range. The army has stated that the GLM will be the 'initial' grenade launcher for whatever weapon is eventually chosen to replace the M16/M4.


The service bought an initial 1200 weapons in fiscal year 2007 (FY07) for delivery from December 2008, 7497 in FY08, also for delivery from December 2008, and has requested funding to buy 9342 in FY09; the army plans to field 36,696 GLMs through FY13.

The M320 is based on the AG36, which in the 1990s H&K developed in parallel with the 5.56-mm G36 assault rifle for the Germany Army. In German service the AG36 replaced the single-shot H&K 40mm HK69A1 stand-alone grenade launcher. An advantage of the AG36/ M320 is that the barrel pivots to the side so the weapon does not need to be raised from the ground to be reloaded and this design also allows the use of extended-length ammunition. The AG36 can be fitted to the standard 48-cm G36 barrel and 39-cm close quarter battle barrel. More than 30,000 have since been produced for customers in Germany, the Netherlands, Portugal, Spain and Britain.

The British Ministry of Defence acquired the AG36 to meet an urgent operational requirement to boost the firepower of British troops deployed in Afghanistan and Iraq; every four-man fire team within the British Army, Royal Marines and Royal Air Force Regiment includes one grenadier. This distribution is typical of many armies. The selection of the AG36 for use with the SA80 5.56-mm assault rifle builds on the relationship established when H&K upgraded the weapon to the much-improved SA80A2 standard. A quadrant sight has been fielded for use with the AG36 and fire team leaders use the new PLR 15c Commanders Target Locating System, a 1500-metre range laser rangefinder, to provide the grenadier with the range to the target. As part of the Future Integrated Soldier Technology Increment la, planned to achieve an initial operational capability in late 2010, the army is seeking to acquire medium-velocity ammunition to extend the range of the UGL to 800 metres.

H&K developed the HK416 Grenade Launcher Module, a variant of the AG36, for use with its HK416 5.56-mm weapon designed in co-operation with the US Special Operations Command (Socom) as an enhancement to the M4 carbine. Small numbers of HK416s are being used by special forces in Afghanistan and Iraq.


To replace the M4 Socom is now fielding the FN Herstal Special Operations Forces Combat Assault Rifle (Scar) family, which consists of the 5.56-mm Mk 16 Scar-Light, the 7.62-mm Mk 17 Scar-Heavy and the 40-mm Mk 13 Enhanced Grenade Launcher Module (EGLM), which can be fitted to both models as well as the M4A1 carbine. Originally a separate request for proposals had been issued for an ELGM to replace the M203 in January 2004, but two months later it was merged with the Scar project. The ELGM leverages technology from the 40-mm UGL developed as part of the company's F2000 5.56-mm Modular Assault Weapon System. The EGLM consists of the grenade launcher, a fire control system and a buttstock assembly to allow the EGLM to be used as a stand-alone weapon. The FN Herstal launcher weighs 1.3 kg and measures 30 cm in length when used in the under-barrel mode; the standalone weapon weighs 2.7 kg and measures 67.5 cm with buttstock extended. The ELGM fires standard 40 x 46 mm munitions, special low velocity munitions and can also accommodate longer munitions than the M203. A Special Operations requirement is that the 'Increment 1' ELGM can be upgraded to fire 'Increment 2' programmable munitions. Under an eight-year indefinite delivery/indefinite quantity contract up to 21,000 launchers, 25,000 fire control units and 25,000 butt-stocks could be ordered.


Singapore Technologies Kinetics (STK) developed the single-shot 40-mm CIS 40GL in the late 1990s as a UGL attachment for its new 5.56-mm Sar 21 small arms family. The 40GL can also be used as a standalone weapon.

STK is one of the world's largest manufacturers of 40-mm ammunition. At Eurosatory 2008 STK introduced its new 40-mm Low Velocity Air-Burst Munition System (LV ABMS). This exploits the work already done by STK developing time-based fuze technology for the high-velocity 40-mm ABMs fired by the company's 40-mm Automatic Grenade System (AGS) and Lightweight AGS. The 40-mm LV ABMS comprises the ABMs and a fire control system designed to clip on top of all new and existing 40-mm UGLs, including STK's CIS 40GL and the M203. The fire control system includes a red dot sight and a laser rangefinder with a maximum range of 500 metres, which can be extended to 800 metres if the customer requires. The 40 x 46-mm ABM ammunition is armed 14 to 28 metres from the weapon and has a maximum range of 400 metres. Each fuze incorporates a built-in self-destruct feature. According to STK officials, production is ready to begin as soon as an order is received.

Beretta has developed the ARX 160 5.56-mm assault rifle and GRX 160 40 mm single-shot UGL to replace the Beretta AR 70/90 5.56-mm assault rifles now in Italian Army service. For use with the GRX 160, Galileo Avionica has developed the Scorpio Grenade Launcher Fire Control System, which incorporates an integral laser rangefinder and ballistic computer, allowing grenades to be accurately delivered out to 400 metres. The army intends to equip two grenadiers in each squad with the GRX 160.


Nexter Systems and Lacroix Defence & Security have teamed to develop the Leap (Light Equipment Airbursting Programmable) system to meet an urgent requirement from the French Army to upgrade the M203 used with its Famas 5.56-mm assault rifle. The Leap consists of the improved M203PI, a multi-purpose interface, an 'Operation Pad' man-machine interface, a fire control system and new 40-mm programmable airburst ammunition. The fire control system, which can be used to fire 5.56-mm, 40-mm ABM and rifle grenades, incorporates a laser rangefinder, a red dot system, a shot counter, optional compass and a link to the Firewire digital open bus architecture used in the Felin (Fantassin Equipements et Liaisons Integres) which Sagem Defense Securite is developing for the French Army.

Semi-automatic Fire

In 2005 the US Marine Corps began fielding the Milkor USA 40-mm M32 Multiple Shot Grenade Launcher. The project was launched following a symposium at which senior non-commissioned officer weapon specialists agreed that the M203 should be replaced as a matter of urgency. The M32 measures 812 mm in length and weighs 5.9 kg empty. It has top-mounted reflex optical sights and features four Mil-Std-1913 rails on the fore end. A trained M32 gunner can fire six aimed rounds in less than three seconds. << The M203 was one shot at a time. The M203 became a signal weapon. This is more of an offensive weapon. With this, you shoot, adjust and fire for effect, >> said Chief Warrant Officer 4 Gene Bridgman. The M32 is based on the six-shot revolving MGL-140, which in turn is based on the MGL developed by Milkor of South Africa; since 1980 the company has produced more than 18,000 units for military customers in at least 30 countries.

Rippel Effect, as the South African company has been rebranded, has recently introduced the XRGL40 extended range grenade launcher, which weighs 20% less than earlier designs and fires 40 x 46 mm rounds to 375 metres and extended-range, low-pressure 40 x 51-mm rounds to 800 metres. Denel Munitions is collaborating with Rippel Effect in the development and production of the extended-range low-pressure ammunition.

Australia's Metal Storm is collaborating with ST Kinetics and Electro-Optic Systems of Australia to develop various applications of its electronically initiated superposed load weapons technology including the 3GL semi-automatic 40-mm grenade launcher. This can be mounted on various weapons such as the M16, the Sar21 and the Steyr Aug (in Australian Army service as the F88) and can also be used as a stand-alone weapon. The 3GL contains up to three stacked rounds that can be loaded individually with ammunition types mixed to suit the mission.


The first fully functional 3GL prototype was tested in June 2007 and various improvements have been introduced into subsequent prototypes. According to Metal Storm Chief Executive Officer Lee Finniear, << We will be firing many thousands of rounds [this year] and performing a range of environmental, electromagnetic, shock and ballistics testing to qualify the weapon sufficiently for safe operation by military forces during independent trials >>. He expects to have 3GL weapons ready for production and delivery to customers before the end of 2009.

Extended Reach

Martin Electronics (MEI) of Perry, Florida has developed the Mercury MV 40-mm medium velocity round. With a muzzle velocity of 107 metres/sec the Mercury has double the reach of the M433 with a maximum range of 800 metres, double the explosive fill and 45 % more fragmentation effect. The Mercury has demonstrated an accuracy of about seven metres at a range of 800 metres and has achieved a range of 950 metres. The British Chemring Group acquired MEI in June 2008 for $ 70 million and is actively marketing that company's products to the British Ministry of Defence and other European customers.


MEI produces the Hellhound round, which has twice the lethal radius of the M433 and is able to breach doors before exploding inside a room, and the Draco thermobaric round, which is also optimised for urban operations. Following discussions with American soldiers and marines about their combat experiences in Iraq, MEI developed the 40-mm High-altitude Unit Navigated Tactical Imaging Round (Huntir). Squad and platoon leaders identified the need for an aerial surveillance system that could be immediately deployed to locate targets in urban operations. Fired from the M203 the Huntir climbs to an altitude of about 230 metres then ejects an infrared complementary metal-oxide semiconductor camera. Suspended from a small parachute the camera provides up to five minutes of real-time video to a pocket personal computer or similar monitor. MEI built an initial 5000 rounds for evaluation by the US Marine Corps and the British and Swedish armies. MEI has since incorporated digital technology to improve resolution.

A 25 mm Future?

An element of the US Army's cancelled XM29 Integrated Airburst Weapons System, intended to replace the M16/ M4 series and M203, may survive: the XM25 Airburst Weapon System developed by Alliant Techsystems (ATK), H&K and L-3 Brashear. The weapon is intended to engage point targets at 500 metres, area targets out to 700 metres and targets behind cover. This is achieved through the use of ATK's new programmable 25-mm low-velocity airburst munition family and L-3's XM104 FCS system, which integrates direct-view optics, a laser rangefinder, compass, ballistic processor, fuze setter and internal display. The rangefinder determines the distance to the target and this data is fed into the firing mechanism which programs the fuze. The fuze calculates the velocity as the round flies toward the target and detonates the round precisely at the intended point.

To defeat a sniper located in a window 300 meters away a soldier would programme the XM25 to airburst at a range of 301 meters so that it explodes inside the room. A small number of XM25 prototypes were delivered to the army in 2005 for testing. The 25 mm ammunition family includes high explosive airburst, armour-piercing, anti-personnel, non-lethal (blunt), non-lethal (airburst), breaching and training rounds. Officials from the US Army's Program Executive Officer Soldier describe the XM25 as a potential 'far-term', beyond 2014, system.

In the near-term the US Army, as with other armies, is seeking to exploit the potential of both new launchers and ammunition which will ensure that 40 mm remains the standard calibre of UGLs and shoulder-fired weapons for decades to come.

KBP's Move to 40 mm

While it presented its traditional-calibre (43 mm) four-shot GM-94 at the Kuala Lumpur DSA exhibition in early 2004 (left), KBP used the venue to unveil its new 40-mm six-round 6G-30 (centre). The revolver carrier is rotated by a pre-wound spring and fires caseless Vog-25 and Vog-25P ammunition. The rounds are muzzle loaded. Tipping the scales at 6.2 kilos, the 6G-30 has a rate-of-fire of 16 rds/min and a range of 400 metres. The picture taken by Armada of the Denel-Milkor AGL (right) at a firing demonstration in South Africa offers an interesting comparison.

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Title Annotation:Infantry: weapons
Author:Kemp, Ian
Publication:Armada International
Date:Oct 1, 2008
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